ka2zev
90
70-440B
What it looks like with the covers on.
What we need to do for this conversion.
The idea is to make the minimum number of 'hack's' and still have a working unit.
Also remove anything that might cause issues with the item in service.
Document what has been done in the event something needs repair later on.
I try to use Radio Shack items when ever possible to insure access to nessessary parts.
The most critical thing to do is bench check and convert for ham 2m operation. This is to make sure it is solid before starting.
It is my hope that this is not your first Midland Project.
To work in Syntech 1 you will need an E Prom ereaser and a custom Midland Programer.
The programer is expensive.
Check with the guys on the Midland LMR list for vendor sources.
Usually for a small amount one of the members there will erease your prom and program new data on it.
First you have to see if the radio you have is working properly.
I have a set of accecories to do just that.
Hook it up as you would in a mobile instalation.
Control head, cable, microphone and speaker.
If the radio it's self is not good to begin with, the rest is pointless.
Pull the E Prom module read it, and see if the radio works 'as you got it'.
This simplifies a lot of pain later on.
If the radio is good, do the usual conversion to 2 Meter ham service.
9-2010
Got some coments from a client and you know he was right. Im going to take my remarks and inject there in here, choping out things that may not be too exciting for the rest of you.
........................................................
I've only tried to modify one other 70-340B for 2m before, and its PLL still falls out of lock on occasion, so I don't know the best way to get a 70-340B down to 2m.
(I presume you can program an SY 1.
Just because we can program a radio, don't assume it's going to work there.
When you get a new radio, for the moment leave the radio stock.
Do not try to do the aprs mods.
Test it like a normal unit.
What I do is have a standard program where I put in frequencies from
159.025 down to 140.025 in 1mhz steps.
With a narrow space radio like a 340 you will be in lock for about 4 mhz of that range.
If you look on the syntho side of the radio, you will see two 'cans'. One is the RX vco and the other is the TX vco.
I strongly recomend a small drop of oil on the slug since it will bind and crack with the plastic it's been part of since the day it was made.
With a ceramic tuning tool you can carefully adjust the slug in this can.
There are also test points to clip on wires to in order to get the VCO voltage.
These help loads!
In the manual that I do not have handy there is a tune up procedure to do this.
Then you have to align the rest of the radio.
So when you get the radio working good in the ham band, you can do the APRS conversion.
I usually put it on the air for a while and talk on it, just to make sure it's going to stay and work properly.
I program up another e prom for 144.39 TX and RX with no tone.
Just for grins I put it on the space for channel 39 and leave the rest blank.
I also set the time out timer for 30 seconds in the event the TT3 fails in TX mode.
I test the radio with this next e prom and make sure it all works.)
so I wanted to see what are your "best practices" for either sticking a TinyTrak3 inside the 70-340B housing or hanging it off the back.
What your missing is tuning up the radio to work in the ham part of the band.
(What I do is the same thing if you had to convert a 159 radio to a 154 radio.
They tune down to 143 just fine.
Do it in small steps and it works like a champ.)
My way takes a lot of wire work but in the end it's a very solid conversion.
Some have over 30k hits into the system.
Of the 25 or so that are on the air, I am well over the 250k recorded hits into the system.
Not bad for junk radios.
Been playign with some TT4 units
www.flickr.com/photos/90108848@N00/sets/72157624707423603/
Got two in the works right now.)
.......................................................
Do a real good tune up on 144.39, or slightly off channel if local users are getting signal into your radio.
Program up the channel element for
Ch RX TX
39 144.39 144.39
I usually set the Time Out Timer for 30 seconds.
That way if the controler 'hicks up' the radio will not tie up the channel for more than that amount of time.
Turn off all the scan functions.
Be sure the Busy Channel Lock Out is turned off.
Some of the things we are going to do.
If the radio has a PL board in it, we will be removing the board and by passing that system.
Save the PL board because it will become a source of various color wires we will need later on.
Remove the 'nose peice' exposing a bunch of easy to get at connection points for the APRS module.
Re work the radio's wire harness to adapt to the APRS module's control.
Fabricate a power control relay system for the APRS module to operate.
By pass the squelch control and a volume control.
As of Feb 26 2009 I have two prototpyes finished.
-10 and -11. You will see them in these photos.
The good ideas from the first two will make the -12 an easy to produce item for most everybody and be the final 'rev' in the series.
The key variants so far.
-10 has a lot of wire splices in it.
-10 used single turn pots for volume and squelch.
-11 used mostly wires that were inside the radio it's self.
-11 used multi turn pots for voulme and squelch.
In the -12 the plan is to use fixed value resistors.
This will set the rx audio gain and the squelch point to consistant values.
For trimming we can make use of internal pots already built into the radios.
5-20-2009
This worked out very well.
-13 became a conversion of a Yeasu 1802 unit.
-14 was completed last weekend.
It's the slickest one so far.
-15 will be photographed for inclusion in this article.
6-24-2009
-16 conversion taught me a few things and a couple of minor values in the charts changed.
-17 went very slick.
90
70-440B
What it looks like with the covers on.
What we need to do for this conversion.
The idea is to make the minimum number of 'hack's' and still have a working unit.
Also remove anything that might cause issues with the item in service.
Document what has been done in the event something needs repair later on.
I try to use Radio Shack items when ever possible to insure access to nessessary parts.
The most critical thing to do is bench check and convert for ham 2m operation. This is to make sure it is solid before starting.
It is my hope that this is not your first Midland Project.
To work in Syntech 1 you will need an E Prom ereaser and a custom Midland Programer.
The programer is expensive.
Check with the guys on the Midland LMR list for vendor sources.
Usually for a small amount one of the members there will erease your prom and program new data on it.
First you have to see if the radio you have is working properly.
I have a set of accecories to do just that.
Hook it up as you would in a mobile instalation.
Control head, cable, microphone and speaker.
If the radio it's self is not good to begin with, the rest is pointless.
Pull the E Prom module read it, and see if the radio works 'as you got it'.
This simplifies a lot of pain later on.
If the radio is good, do the usual conversion to 2 Meter ham service.
9-2010
Got some coments from a client and you know he was right. Im going to take my remarks and inject there in here, choping out things that may not be too exciting for the rest of you.
........................................................
I've only tried to modify one other 70-340B for 2m before, and its PLL still falls out of lock on occasion, so I don't know the best way to get a 70-340B down to 2m.
(I presume you can program an SY 1.
Just because we can program a radio, don't assume it's going to work there.
When you get a new radio, for the moment leave the radio stock.
Do not try to do the aprs mods.
Test it like a normal unit.
What I do is have a standard program where I put in frequencies from
159.025 down to 140.025 in 1mhz steps.
With a narrow space radio like a 340 you will be in lock for about 4 mhz of that range.
If you look on the syntho side of the radio, you will see two 'cans'. One is the RX vco and the other is the TX vco.
I strongly recomend a small drop of oil on the slug since it will bind and crack with the plastic it's been part of since the day it was made.
With a ceramic tuning tool you can carefully adjust the slug in this can.
There are also test points to clip on wires to in order to get the VCO voltage.
These help loads!
In the manual that I do not have handy there is a tune up procedure to do this.
Then you have to align the rest of the radio.
So when you get the radio working good in the ham band, you can do the APRS conversion.
I usually put it on the air for a while and talk on it, just to make sure it's going to stay and work properly.
I program up another e prom for 144.39 TX and RX with no tone.
Just for grins I put it on the space for channel 39 and leave the rest blank.
I also set the time out timer for 30 seconds in the event the TT3 fails in TX mode.
I test the radio with this next e prom and make sure it all works.)
so I wanted to see what are your "best practices" for either sticking a TinyTrak3 inside the 70-340B housing or hanging it off the back.
What your missing is tuning up the radio to work in the ham part of the band.
(What I do is the same thing if you had to convert a 159 radio to a 154 radio.
They tune down to 143 just fine.
Do it in small steps and it works like a champ.)
My way takes a lot of wire work but in the end it's a very solid conversion.
Some have over 30k hits into the system.
Of the 25 or so that are on the air, I am well over the 250k recorded hits into the system.
Not bad for junk radios.
Been playign with some TT4 units
www.flickr.com/photos/90108848@N00/sets/72157624707423603/
Got two in the works right now.)
.......................................................
Do a real good tune up on 144.39, or slightly off channel if local users are getting signal into your radio.
Program up the channel element for
Ch RX TX
39 144.39 144.39
I usually set the Time Out Timer for 30 seconds.
That way if the controler 'hicks up' the radio will not tie up the channel for more than that amount of time.
Turn off all the scan functions.
Be sure the Busy Channel Lock Out is turned off.
Some of the things we are going to do.
If the radio has a PL board in it, we will be removing the board and by passing that system.
Save the PL board because it will become a source of various color wires we will need later on.
Remove the 'nose peice' exposing a bunch of easy to get at connection points for the APRS module.
Re work the radio's wire harness to adapt to the APRS module's control.
Fabricate a power control relay system for the APRS module to operate.
By pass the squelch control and a volume control.
As of Feb 26 2009 I have two prototpyes finished.
-10 and -11. You will see them in these photos.
The good ideas from the first two will make the -12 an easy to produce item for most everybody and be the final 'rev' in the series.
The key variants so far.
-10 has a lot of wire splices in it.
-10 used single turn pots for volume and squelch.
-11 used mostly wires that were inside the radio it's self.
-11 used multi turn pots for voulme and squelch.
In the -12 the plan is to use fixed value resistors.
This will set the rx audio gain and the squelch point to consistant values.
For trimming we can make use of internal pots already built into the radios.
5-20-2009
This worked out very well.
-13 became a conversion of a Yeasu 1802 unit.
-14 was completed last weekend.
It's the slickest one so far.
-15 will be photographed for inclusion in this article.
6-24-2009
-16 conversion taught me a few things and a couple of minor values in the charts changed.
-17 went very slick.